The sound you hear coming from Mad River Glen and Appalachian Gap this weekend may well be the heavy breathing of runners and riders racing uphill. As part of Mad River's Green and Gold Weekend, two annual, aerobic challenges are on the schedule: the Stark Mountain Hill Climb for runners on Saturday, October 6; and the Allen Clark Hill Climb for cyclists on Sunday, October 7.

The concept behind the Stark Mountain climb is delightfully simple: Get from the bottom of Mad River's single chair to the top in the fastest time possible, by whatever route you choose. That means covering 2,000 vertical feet, with the distance, of course, depending on the route chosen. The fastest runners will make the trip in under a half hour.

The Allen Clark climb is similarly simple: As long as you've got a bike and a helmet, you can try your luck riding the 6.2-mile distance rising 1,600 vertical feet from the intersection of Routes 100 and 17 to the top of Appalachian Gap. Actually, you don't even need a bike -- for this year's event at least two unicyclists are preregistered.

Also similar are the schedules for Saturday and Sunday. Start time for both races is 10 a.m., with registration opening at 8:30 a.m. Registration for Saturday's run will be at the Basebox at Mad River, while registration for Sunday's ride will be at Stark Mountain Bike Works at the Route 100/17 intersection. The entry fee of $25 is the same for either event, with plenty of raffle prizes to be handed out both days in post-event festivities.

A few special bonuses are being dangled as carrots. Any man or woman who can set a new course record for either the run or the ride will receive a $100 cash award. And for those participating in both events, there will be prizes going to duathlon winners.

Regardless of your objectives, however -- whether to set a new record or to embark on a more casual run or ride -- you'll be helping out a good cause. All proceeds from the run go to the Stark Mountain Foundation to aid in the reconstruction of Mad River's single chair. Proceeds from the bike race go to Vermont Adaptive Ski and Sports.